COVID-19 May Awaken Dormant Viruses, New Research Reveals Potential Link - Video

A new study published in Nature suggests that COVID-19 may reactivate viruses that have remained hidden in the body for years. Researchers found evidence of viral reactivation in nearly half of hospitalized COVID-19 patients, including people without obvious immune suppression.

Some viruses remain in the body after an initial infection but stay largely inactive under immune control. Herpesviruses such as Epstein-Barr virus (EBV), cytomegalovirus (CMV), and herpes simplex virus 1 (HSV-1) are examples. Severe illness or changes in immune activity can allow these viruses to become active again, a process known as viral reactivation. Importantly, reactivation does not necessarily mean a new infection.

The researchers analyzed 1,154 people hospitalized with COVID-19 across 20 US hospitals between May 2020 and March 2021. They examined blood, nasal swabs and, in some mechanically ventilated patients, airway samples for genetic evidence of viruses other than SARS-CoV-2.

Overall, 47.9% of participants with available data showed evidence of at least one viral reactivation during acute COVID-19.

EBV tended to reactivate earlier during illness, while HSV-1 and CMV were more likely to appear later. Researchers also detected viruses from the Anelloviridae family, which are common in humans but remain poorly understood.

Several viral signals were associated with greater COVID-19 severity and complications. Some were also linked to poorer long-term outcomes in certain severely ill patients.

However, the researchers emphasized that the findings show associations, not cause and effect. The study cannot establish whether viral reactivation directly worsens COVID-19 or contributes to long COVID.

The findings nevertheless suggest that severe COVID-19 may disturb the body's balance with previously controlled viruses. Understanding these interactions could eventually help scientists identify biomarkers of severe disease and uncover new pathways involved in long COVID.

REFERENCE: Maguire, C., Chen, J., Rouphael, N. et al. Virus reactivation in acute and long COVID-19. Nature (2026). https://doi.org/10.1038/s41586-026-10740-z